ON every 0.5-secs (RED LED) High

Vokera ON every 0.5-secs (RED LED) Fault Code

Also written as ONEVERY05SECSREDLED — same fault.

The Vokera ON every 0.5-secs (RED LED) fault code means: your boiler has detected a critical internal safety fault and has locked itself down to prevent damage, meaning it will not provide any heating or hot water until a professional engineer repairs it.. It appears on 1 Vokera model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Final fault, e.g.: water pressure switch, condense pressure switch, fan/flue problem, limit thermostat
Typical repair cost £120-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Vokera models that show the ON every 0.5-secs (RED LED) fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Vokera ON every 0.5-secs (RED LED) fault code information on this page is sourced and cross-checked against the official Vokera service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026